Installing the FL instrument cluster in a '06 Focus is not a nightmare. I have done it in my ST a few months ago (many thanks to JW1982!). It can be done at home, but an additional particular interface/software is needed. I used "FoCom" for this. It is sometimes available on Ebay for 40-70 Euros. This is the price for a simplified, chinese version, but for pairing the keys with instrument cluster and ECU it is perfect. The only little drawback is that an on-line internet connection is needed during pairing, but it can be avoided using one of easily available outcode/incode generators. It is important to backup every configuration (except HEC Page 3) of the old instrument, and to tick "HEC Level 2/3" and "Clock" in a new one.